1. Field of the Invention
The invention is directed at a switching system, preferably a medium-voltage switching system, comprising a power switch or load switch, a disconnecting switch, as well as a grounding switch configured as a vacuum switching chamber.
2. The Prior Art
Electrical switching systems, frequently also configured in gas-insulated form, are particularly used in the sector of medium-voltage technology, and usually possess a disconnecting switch and a grounding switch. The disconnecting circuit and the grounding circuit can be implemented in one switch, as well as a power switch. The disconnecting and grounding switches, which can be brought into electrical connection with one another, as well as the power switch, then connect a bus bar with an outgoing circuit that is connected with several cable connectors, for example. The two switches, namely the disconnecting and grounding switch as well as the power switch, are disposed one after the other, in a common grounded housing, branching off from the encapsulation of the bus bar.
In this connection, the switches are generally disposed on top of one another or next to one another, and are moved in the common direction of movement, in a translational manner. Such a gas-insulated electrical switching system is described in Swiss Patent No. CH 559977 A5. Because the disconnecting and grounding switch and the power switch are arranged vertically on top of one another, a necessary construction height exists, which results from the dimension of the individual switches as well as the dimension of the required disconnecting distance, i.e. the length of the separation distances. Since the two switches are disposed vertically on top of one another, the lengths of the individual components and separation distances add up to produce the required construction height.
In this connection, it is true that it is already possible to configure the power switch as a vacuum switch and thereby to reduce the required separation distance, which is clearly smaller in a vacuum than in a gas atmosphere. Thus, a switching system of the type stated is known from German Patent No. DE 102 19 299 B3, in which the power switch and the disconnecting switch are configured as a structural unit. However, the disconnecting switch is located further in the inert gas atmosphere, so that a separation distance path corresponding to the surrounding gas atmosphere is required to form a reliable separation distance. Furthermore, in the case of the switching system known from this document, a grounding switch configured as a vacuum switch is provided, which is disposed perpendicular to the power and/or power disconnecting switch. For grounding, which takes place after the power disconnecting switch has been brought into its disconnecting position, the moving contact of the vacuum switch is moved towards its fixed contact from the outside. In the case of this embodiment, as well, there is a relatively great construction height, since the disconnecting part of the power disconnecting switch is configured in the gas atmosphere, and there, a separation distance that assures disconnection of the electrical conduction connection must be configured.
European Patent No. EP 1 218 995 B1 describes a gas-insulated electrical switching system, which has an interruption unit having a fixed contact and a movable contact, as well as a disconnecting and grounding switch configured as a rotary switch, which is disposed on the side of the fixed contact of the interruption unit. Different disconnecting and grounding positions can be set by means of the rotary switch. With this system, however, both the disconnecting and grounding switch and the interruption unit with its fixed contact and its movable contact are, once again, disposed in an insulating gas atmosphere. Here again, the separation distances required under the conditions of the insulating gas must therefore be adhered to.
EP 0 680 063 B1 describes configuring a power or load switch in the form of a rotary switch having a pole bridge that can be rotated, whereby at the same time, a tappet connected with a movable contact of a vacuum switch is activated by means of a control cam configured on a movable contact of the pole bridge.
With known switching systems, at least the separation distance of the disconnecting and grounding switch, but also, if applicable, the separation distance of the power switch, in addition, are situated in a gas atmosphere of insulating gas. This makes it necessary to configure relatively long distances between the contacts that form the separation distance, in each instance, to assure a sufficient separation distance, in order to avoid flash-over or leakage paths. This has the result that such gas-insulated switching systems are configured to be very voluminous and as a correspondingly large structural unit.